It's really too bad. He had just announced on twitter that a medical procedure had gone well and it sounded like he had more time. He did alot of great for gaming in general.
I tend not to speculate, but 7 days after an invasive procedure with someone in his condition; I can't help but think it was complications from the surgery.
Who is he, some rapper?
One of the pioneers in the youtube video game blogger sphere (or whatever you'd call it). Did video game reviews by playing the game to show you what it was about, often highlighting good but obscure titles, while adding some of his own production value to the video's.
I don't really watch too many youtubers but I think that's about right?